Underwater rock core sampling device and method of use thereof

ABSTRACT

A rotary diamond rock core drill capable of obtaining a threequarter inch diameter core four inches long at any depth down to 6,000 feet is provided. The drill is adapted to be used with manned deep submersibles and is operated by the submersible&#39;&#39;s power supply. The drive motor is encased in an oil-filled, pressure-compensated chamber. A water pump in the drill maintains a steady low pressure flow of water against the sample during drilling operations, washing away rock chips and mud. The water flow may be reversed after the core has been cut, holding the specimen within the core tube as the drill is extracted from the rock outcrop. The sample is then ejected by again reversing the drive motor and pump, forcing the water flow down through the core tube and expelling the specimen.

United States Patent Winget et al.

[54] UNDERWATER ROCK CORE SAMPLING DEVICE AND METHOD OF USE THEREOF [72]Inventors: Clifford L. Winget, Woods Hole; George W. Gibson, E.Falmouthi William S. Shultz, Cataumet, all of Mass.

[73] Assignee: The United States of America as represented by theSecretary of the Navy [22] Filed: Aug. 26, 1970 [21] Appl. No.: 66,935

[52] US. Cl ..175/6, 175/58, 175/330 [51] Int. Cl. ..E21b 3/10, E2 lb7/12, E21b 49/02 [58] Field ofSearch... ..l75/6,58, 75,78,93, 103,

[ 51 May 23, 1972 Primary Examiner-Stephen J. Novosad Attorney-R. S.Sciascia, L. l. Shrago and C. E. Vautrain, Jr.

[ ABSTRACT A rotary diamond rock core drill capable of obtaining athreequarter inch diameter core four inches long at any depth down to6,000 feet is provided. The drill is adapted to be used with manned deepsubmersibles and is operated by the submersibles power supply. The drivemotor is encased in an oilfilled, pressure-compensated chamber. A waterpump in the drill maintains a steady low pressure flow of water againstthe sample during drilling operations, washing away rock chips and mud.The water flow may be reversed after the core has been cut, holding thespecimen within the core tube as the drill is extracted from the rockoutcrop, The sample is then ejected by again reversing the drive motorand pump, forcing 10 Claims, 4 Drawing Figures PATENTED MAY 2 3 I972 sum1 UF 3 PATENTEBMAY 23 I972 SHEET 2 OF 3 a/M/W/ z. 1% fear 6 M fllaon1407/2/22 .5 5/71/47 UNDERWATER ROCK CORE SAMPLING DEVICE AND METHOD OFUSE THEREOF The invention described herein may be manufactured and usedby or for the Government of the United States of America forgovernmental purposes without the payment of any royalties thereon ortherefor.

This invention relates to bottom core samplers and, more particularly,to a rock core sampler for use with manned deep submersibles.

Previous methods of and means for obtaining hard rock specimens from thedeep ocean have been operated from a floating vessel or a dredge, the'sample collector being towed along the bottom by the surface vessel. Itis obvious that the precise location of the sample is not ascertainableby these methods. With the advent of manned deep submersibles, it becamepossible to pick samples off the bottom instead of the blind recoverypreviously practiced. The source of the sample thus obtained, however,still cannot be definitely ascertained since the sample may have beentransported appreciable distances by a variety of forces. To obtainsamples from known locations using manned deep submersibles required thedevelopment of a device which could be controlledby per sonnel in themanned deep submersible. The present invention provides a drill whichmay be controlled by the mechanical manipulator hand of the deepsubmersible and also provides novel means for continuously removingloose material from the drill face, maintaining a sample in the drillduring retrieval and ejecting the sample from the drill at any desiredtime.

Accordingly, it is an object of the present invention to provide a rocksampling device for use with manned deep diving submersibles.

Another object of this invention is to provide a rock sampling devicewhich may be operated by personnel in and power from a manned deepsubmersible and may be controlled by conventional mechanical manipulatorhands on the submersible.

A further object of the invention is to provide a rock sampling devicewhich is capable of obtaining hard rock cores of substantially inchdiameter and 4 inches long from ocean depths down to 6,000 feet usingexiting control devices.

Other objects, advantages and novel features of the invention willbecome apparent from the following detailed description thereof whenconsidered in conjunction with the accompanying drawings in which likenumerals represent like parts throughout and wherein:

FIG. I is a schematic diagram showing the major components of theinvention;

FIG. 2 is a sectional plan view of a component of the schematicembodiment shown in FIG. 1;

FIG. 3 is a longitudinal sectional view of a second embodiment of theinvention; and

FIG. 4 is a schematic view of a third embodiment of theinvention beingoperated remotely from a manned deep submersible.

Referring to FIG. 1, there is shown the deep core drill 11 whichincludes a tubular shell 12 housing in longitudinal succession a DCmotor 13, a gear reducer 14, a universal joint 15, a flexible impellerwater pump 16 and the upper end of a hollow drill shaft 17. Theforegoing components are interconnected and are disposed in separatecompartments. These components are adapted for operation in either aclockwise or counterclockwise direction depending on the particular use.Motor 13 is disposed in a chamber 20 which is filled with a pressurecompensating oil 21 having high dielectric characteristics. The oiloccupies several compartments and is separated from the seawater bymeans of a free-floating piston 24 which is slidably mounted on a pumpshaft 25. Drill shaft 17 is connected to shaft 25 and is provided with aport 26 at the upper end for admitting seawater, an enlarged cavity 27which is open at its remote end to receive the core sample and aninterconnecting passage 28. Drill shaft 17 is provided with a collar 29at its remote end which collar is fitted with a plurality of diamondtips 30 for cutting into the bottom rock. Housing 12 is provided with anopening 33 for admitting seawater into a seawater chamber 34 belowpiston 24. Seawater enters pump 16 through an inlet 35 in chamber 34 andexits the pump through an outlet 36 into a plenum chamber 37 between thelower face of the pump and the bottom of housing 12. Drill shaft 17 issecured to pump 16 by conventional means, not shown, and rotates in abearing 40 in the bottom end of housing 12. A T-handle 38 is providedfor securing into a threaded opening 39 in theupper end of housing 12.The handle 38 used is selected to mate with a submersible manipulatorhand, the handle having a T-bar 40 for providing rotary control and ashaft 41 for providing longitudinal control.

FIG. 2 shows pump 16in transverse view, the pump including a casing 42within which impellers 43 rotate, and a ramp '44 which substantiallydeforms the impeller arms so as to apply a sufficient pressure to forcewater through outlet 36.

In'the embodiment of FIG. 3, T-handle 50 is mounted in an end cap 51which is secured to an outer drill housing 52. An inner drill housing 53contains a drive mechanism 54, a universal joint 55, a pump assembly 56and an end fitting 57 which has a flange 58 extending a sufficientdistance outward to provide an abutting surface to receive a shockabsorbing spring 59. Outer housing 52 slides over inner housing 53 on aplurality of nylon slide buttons 63 which are secured in outer housing52. Electrical power supply lines 64 are received through an attachment64 to inner housing 53. The power lines are removably connected by meansof a connector 67. Drive mechanism 54 is contained in a chamber 68 whichis filled with a pressure-compensating oil 69 as in the embodiment ofFIG. 1. The pressure-compensating oil is admitted through dividers 70,71 and 72 into a chamber 73 which is positioned above a diaphragm 74whose transverse surface is disposed between a flange 75 and a clampplate 76. Diaphragm 74 encloses a water chamber 77 by means of whichseawater pressure is applied to compensating oil 69 to maintain theentire device under equal pressure. Water is admitted into chamber 77 bypassage 78, into pump 56 by passage 79. Water is discharged from pump 56through a connecting port 80 and into a hollow drill shaft 81 which issecured to pump 56 and traverses a bushing 82 which is disposed in endcap 57. Drill shaft 81 is provided with a core receiving chamber 83,water entering chamber 83 through a port 26 and a passage 84 in theupper portion of shaft 81. Flange 75 is mounted on a drive shaft 85 andis secured to the pump housing by a spring 86. A grease fitting 8 alsois provided.

FIG. 4 illustrates another embodiment of the invention secured in amechanical hand manipulator 91 which is connected to an arm 92 extendingfrom the submersible hull. The

-core sampler 90 is substantially identical in internal components tothe embodiment of FIG. 3; however, the outer casing has been replaced bya pair of spring restraining members 94 and 95, and a shock absorbingspring 96 is disposed between members 94 and 95.

In operation, the rock core drill is secured in the manipulator hand asindicated in FIG. 4, and the drill shaft 97 is disposed at an angle of50 to 60 to the rock surface to enable a starting cut to be made. In themanipulator shown, the bar of the T-handle is nested into a notchedsection at the base plate of the fingers with the fingers grasping thehandle shaft. The drill is operated at the angle indicated until aslight moonshaped groove is cut in the rock. The groove need not exceedone-sixteenth to one-eighth of an inch in depth; and, after this depthis reached, the assembly is slowly brought to a vertical position andthe cut continued until the required core length has been reached. Ifthe drill is not initially positioned at an angle, it will wander offfrom the initial point and be extremely difficult if not impossible tostart the drilling action.

At the proper depth of penetration, the direction of the motor rotationis reversed, reversing the pump impeller and, consequently, thedirection of water flow. Drilling action continues with the drillrotating in the opposite direction, but the mud now is not flushed outand instead begins to thicken at the base of the core hole. The drillassembly at this time preferably is rocked slightly to assist in seizingand breaking off the core specimen. The specimen is retained in thehollow core of the diamond drill by the slight suction maintained by thereverse water flow action of the impeller pump. The core drill next isremoved from the hole and the rock core is deposited in a receptacle byagain reversing motor rotation which reverses water pump flow, ejectingthe rock core from cavity 27 of drill shaft 17. Additional hard rockcores may be obtained at once by repeating the drilling procedure.

Deep water operation of the drill has indicated that a restrainingtorque on the order of 23 in. lb. is suflicient in a selected vehicle tocounteract the torque generated by the motor. Larger rotary drills orside wall sampling while the vehicle hovers at the side of a verticaloutcrop will probably require the use of a holding dew'ce such as asuction pod or a driven piton.

The embodiment in FIG. 3 is the preferred embodiment of the inventionand includes the two housings 52 and 53 which preferably are made ofaluminum and are protected from both abrasion and corrosion through theuse of an electrochemical coating of aluminum oxide. When T-handle 50 isdepressed by the operator, the stainless steel compression spring 59provides a constant 30-pound downward thrust on the drill bit. Theconstant load assures the operator of optimum bit per formancethroughout the drilling cycle and tends to smooth out any spasmodicmotion of the mechanical manipulator. The linear travel of the constantload spring is three inches.

Both the power cord and the motor/gear box assembly are fully pressurecompensated. The oil reservoir is located within the drill housing andhas sufficient capacity to assure complete compensation of the powercord. Without compensation, the power cord becomes still andunmanageable when exposed to the elevated hydrostatic pressuresencountered at the operational depths of the vehicle.

Twisting between inner housing 53 and outer housing 52 is prevented by aconnector housing, not shown, which is secured to the inner housing andfree to slide within a slotted guide machined in the side wall of theouter housing. The assembly permits straight line motion as constantload spring 59 is depressed, while preventing rotary motion as a resultof motor torque.

Grease fitting 87 in end cap 57 provides lubrication for thrust bushing82 as well as furnishing a means of flushing the bearing surfaces with alightweight grease.

When drilling under water, pump fluid flow is discharged into plenumchamber 37 through port 26 in hollow drill shaft 81. When in thedrilling perpendicular mode, water flow is reasonably clean and free ofsediment. On breaking off the core and reversing pump flow, mud andsediment is sucked up into the plenum chamber and out through the pumpdischarge. To assure that the mud residue does not penetrate the shaftseal and enter the bearing assembly, a shot of grease preferably isinjected into the bearing at the completion of each dive. To facilitatethe flushing procedure, cup seals, not shown, located at a clamp ring 90and the base of drill shaft 81, are inserted to provide free flow out ofthe bearing area when grease is injected through fitting 87. Such shaftseals assure against rupture or blowout when grease is injected.

Diaphragm 74 is shown in the fully extended or empty position. Undernormal conditions, the oil cavity is pressure filled, compressing spring86 and collapsing the bellows into an accordion-pleated configuration.The total volume of oil contained within the drill in this embodiment issubstantially 760 cc.

The air weight of the assembly of FIG. 3, including compensation oil andcoiled power lead, is 13.6 pounds. Its water weight is 9.7 pounds.

Obviously many modifications and variations of the present invention arepossible in the light of the above teachings. For example, means couldbe provided for marking the magnetic orientation on the core specimenprior to its removal from the parent material.

What is claimed is:

1. A hard rock corer for obtaining rock samples at depths down to 6,000feet comprising:

a closed tubular housing having a handle secured thereto in sealedrelationship at one end and receiving in sealed relationship a hollowdrill shaft at the other end, said housing compartmented to receive insuccession in individual interconnected chambers an electric motor, areducing gear, a universal joint and a piston;

said chambers sealed at said piston from the environment and containinga pressure-compensating oil having selected dielectric characteristicsfor electrically insulating the device from the environment;

a drive shaft extending from said universal joint and connected insuccession to a rotary water pump and said hollow drill shaft,

said piston slidably mounted on said drive shaft in sealing engagementtherewith and with the interior surface of said tubular housing toseparate the oil on one side thereof from water at ambient pressure onthe other side;

an opening in said shell intermediate said piston and said pump foradmitting water under ambient pressure to the portion of said pistonchamber remote from said oil;

a pump inlet disposed in said piston chamber and a pump outlet disposedin an end chamber intermediate said pump and said other end of saidhousing;

said drill shaft having an opening in said end chamber and a corereceptacle at its remote end, a passage connecting said opening and saidreceptacle;

a hard rock core drill secured to the remote end of said drill shaft;and

an electric power supply externally disposed with respect to saidhousing and means connecting said power supply and said electric motor,whereby during drilling said pump will direct water past the cuttingbits, flushing away loose pieces and mud, and during retrieval the coresample will be held in said receptacle by the suction created byreversing said electric motor.

2. The corer as defined in claim 1 wherein said pump includes aplurality of resilient impellers and a ramp for stressing said impellersprior to discharging water through said outlet.

3. The corer as defined in claim 2 and further including a plenumdisposed between said pump and the adjacent end of said housing,

said pump during drilling discharging water into said plenum, and

said opening in said drill shaft centrally disposed in said plenum.

4. The corer as defined in claim 3 wherein said handle is provided witha T-bar at its outer end for mating with a mechanical manipulator hand.

5. Means for obtaining rock core samples at extreme depths by anelectrically powered rotary diamond tip core drill comprising:

a housing compartmented to accommodate in longitudinal succession anelectric motor, drive means connected to said motor by a drive shaft, arotary pump and a plenum; the compartments containing said motor andsaid drive means made watertight and containing a pressure-compensatingoil having high dielectric characteristics;

said drive shaft traversing said pump and connected to a drill shaft;

a free-floating piston slidably mounted on said drive shaft, said pistonexposed on its surfaces adjacent said pump compartment to the waterenvironment through an opening in said housing and on its opposingsurfaces to said pressure-compensatin g oil, said pump having an inletdisposed adjacent said housing opening and an outlet disposed in aplenum intermediate said pump and the adjacent end of said housing; and

said drive shaft having a core receiving receptacle adjacent a diamondtip core drill and a passage communicating between said receptacle andsaid plenum, whereby a lightweight drill having all components exposedto ambient pressure is provided wherein mud and particles are flushedaway during drilling and a core sample is held by suction created byreversing said pump until the sample is recovered.

6. The device as defined in claim 5 and further including a handlesecured to said housing remote from said drill and having a crossbar atits remote end for mating with mechanical manipulator means.

7. The device as defined in claim 6 wherein said pump is provided with arubber impeller having a plurality of impeller arms.

8. The device as defined in claim 7 wherein said pump is furtherprovided with a ramp for stressing said impeller arms prior todischarging water into said plenum.

9. The method of obtaining a rock core sample from extreme depths by anelectrically driven rock core drill comprising the steps of:

surrounding the electric motor of said drill with a sealedpressure-compensating oil having suitable dielectric characteristics;

admitting seawater at ambient pressure into a free-flooding cavityadjacent the motor cavity;

applying water at ambient pressure to said pressure-compensating oilthrough a free-floating piston forming a portion of said cavity;

pumping water from said free-flooding cavity through a ho]- low drillshaft to a core receiving receptacle at the end of the drill shaft toflush away mud and particles during drilling; and

reverse pumping water from said receptacle to said freeflooding cavityafter a core sample has been broken free to hold the sample by suctionin the receptacle until the sample has been recovered.

10. The method as defined in claim 9 and further including the step ofcontrolling the operation of said rock core drill by a mechanicalmanipulator.

1. A hard rock corer for obtaining rock samples at depths down to 6,000feet comprising: a closed tubular housing having a handle securedthereto in sealed relationship at one end and receiving in sealedrelationship a hollow drill shaft at the other end, said housingcompartmented to receive in succession in individual interconnectedchambers an electric motor, a reducing gear, a universal joint and apiston; said chambers sealed at said piston from the environment andcontaining a pressure-compensating oil having selected dielectriccharacteristics for electrically insulating the device from theenvironment; a drive shaft extending from said universal joint andconnected in succession to a rotary water pump and said hollow drillshaft, said piston slidably mounted on said drive shaft in sealingengagement therewith and with the interior surface of said tubularhousing to separate the oil on one side thereof from water at ambientpressure on the other side; an opening in said shell intermediate saidpiston and said pump for admitting water under ambient pressure to theportion of said piston chamber remote from said oil; a pump inletdisposed in said piston chamber and a pump outlet disposed in an endchamber intermediate said pump and said other end of said housing; saiddrill shaft having an opening in said end chamber and a core receptacleat its remote end, a passage connecting said opening and saidreceptacle; a hard rock core drill secured to the remote end of saiddrill shaft; and an electric power supply externally disposed withrespect to said housing and means connecting said power supply and saidelectric motor, whereby during drilling said pump will direct water pastthe cutting bits, flushing away loose pieces and mud, and duringretrieval the core sample will be held in said receptacle by the suctioncreated by reversing said electric moTor.
 2. The corer as defined inclaim 1 wherein said pump includes a plurality of resilient impellersand a ramp for stressing said impellers prior to discharging waterthrough said outlet.
 3. The corer as defined in claim 2 and furtherincluding a plenum disposed between said pump and the adjacent end ofsaid housing, said pump during drilling discharging water into saidplenum, and said opening in said drill shaft centrally disposed in saidplenum.
 4. The corer as defined in claim 3 wherein said handle isprovided with a T-bar at its outer end for mating with a mechanicalmanipulator hand.
 5. Means for obtaining rock core samples at extremedepths by an electrically powered rotary diamond tip core drillcomprising: a housing compartmented to accommodate in longitudinalsuccession an electric motor, drive means connected to said motor by adrive shaft, a rotary pump and a plenum; the compartments containingsaid motor and said drive means made watertight and containing apressure-compensating oil having high dielectric characteristics; saiddrive shaft traversing said pump and connected to a drill shaft; afree-floating piston slidably mounted on said drive shaft, said pistonexposed on its surfaces adjacent said pump compartment to the waterenvironment through an opening in said housing and on its opposingsurfaces to said pressure-compensating oil, said pump having an inletdisposed adjacent said housing opening and an outlet disposed in aplenum intermediate said pump and the adjacent end of said housing; andsaid drive shaft having a core receiving receptacle adjacent a diamondtip core drill and a passage communicating between said receptacle andsaid plenum, whereby a lightweight drill having all components exposedto ambient pressure is provided wherein mud and particles are flushedaway during drilling and a core sample is held by suction created byreversing said pump until the sample is recovered.
 6. The device asdefined in claim 5 and further including a handle secured to saidhousing remote from said drill and having a crossbar at its remote endfor mating with mechanical manipulator means.
 7. The device as definedin claim 6 wherein said pump is provided with a rubber impeller having aplurality of impeller arms.
 8. The device as defined in claim 7 whereinsaid pump is further provided with a ramp for stressing said impellerarms prior to discharging water into said plenum.
 9. The method ofobtaining a rock core sample from extreme depths by an electricallydriven rock core drill comprising the steps of: surrounding the electricmotor of said drill with a sealed pressure-compensating oil havingsuitable dielectric characteristics; admitting seawater at ambientpressure into a free-flooding cavity adjacent the motor cavity; applyingwater at ambient pressure to said pressure-compensating oil through afree-floating piston forming a portion of said cavity; pumping waterfrom said free-flooding cavity through a hollow drill shaft to a corereceiving receptacle at the end of the drill shaft to flush away mud andparticles during drilling; and reverse pumping water from saidreceptacle to said free-flooding cavity after a core sample has beenbroken free to hold the sample by suction in the receptacle until thesample has been recovered.
 10. The method as defined in claim 9 andfurther including the step of controlling the operation of said rockcore drill by a mechanical manipulator.